Advantech WebAccess Stack-based Buffer Overflow
Low RiskICS-CERT ICSA-14-324-01Aug 23, 2014
Summary
Advantech WebAccess versions 7.2 and earlier contain a stack-based buffer overflow vulnerability (CWE-121) that could allow remote code execution. The vulnerability exists in the WebAccess web server component and could be triggered by a specially crafted network request. No patch is available from the vendor.
What this means
What could happen
A stack-based buffer overflow in Advantech WebAccess could allow an attacker with network access to run arbitrary code on the web server, potentially altering monitoring displays, changing setpoints in connected PLCs, or disrupting SCADA operations.
Who's at risk
Water and electric utilities using Advantech WebAccess for SCADA monitoring and control. Particularly relevant if WebAccess is exposed to engineering networks or internet-connected monitoring interfaces, or if it directly interfaces with remote terminal units (RTUs) or programmable logic controllers (PLCs).
How it could be exploited
An attacker sends a specially crafted network request to WebAccess that overflows a stack buffer. This overwrites return addresses in memory, allowing the attacker to inject and execute arbitrary code on the server with the privileges of the WebAccess process.
Prerequisites
- Network access to WebAccess web server port
- WebAccess version 7.2 or earlier installed
remotely exploitableno patch availablestack-based buffer overflow enables arbitrary code executionaffects SCADA supervisory control systems
Exploitability
Low exploit probability (EPSS 0.3%)
Affected products (1)
ProductAffected VersionsFix Status
WebAccess: <=7.2≤ 7.2No fix (EOL)
Remediation & Mitigation
0/4
Do now
0/2HARDENINGImplement network segmentation or firewall rules to restrict access to WebAccess to only authorized engineering workstations and control networks. Do not expose WebAccess to untrusted networks.
HARDENINGMonitor WebAccess logs and network traffic to the web server for signs of exploitation attempts (unusual request patterns, unexpected connections).
Schedule — requires maintenance window
0/1Patching may require device reboot — plan for process interruption
HOTFIXContact Advantech support to inquire about security patches or migrate to a newer, supported version of WebAccess if available.
Long-term hardening
0/1WORKAROUNDDisable or remove WebAccess if it is not in active use. If the system cannot be updated, consider retiring the affected version.
CVEs (1)
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